Re: RAID5 for Oracle 7.3 on NT 4

1. Why would the drive letters change? Are you saying that some of the logical drives containing parts of your database are mapped to a different server? Even if that's the case, why would the mappings change?

2)I wish I knew. I've never been able to get any truely useful information from PERFMON. Lots of factual numbers, but no useful interpretation of those numbers.

3)Building a strip and mirrored set is commonly referred to as RAID 0+1. I've never used it but seen it referenced a lot. I think it requires that you use the controller to set up the strip set (raid 0) then use the OS to set up the mirror set (raid 1). Since you're using Compaq gear, you might be interested in a white paper from them entitled "Configuring Compaq RAID Teachnology for Database Servers." I have a hard copy, but their web site has quite extensive search capabilities, so you shouldn't have too much trouble locating it.

One thing to be aware of when you consider the performance of various configurations (and read test reports) is whether or not the raid is implemented in hardware (at the controller) or software (at the OS). The Compaq RAID controllers are quite fast and intelligent. We put our databases on RAID-5 arrays and have not had any performance problems. That's not to say that we wouldn't if we excessivly "write heavy." It's just that there are too many variables to be making blanket statements that "raid-5 is too slow."

--
Ed Stevens
(Opinions are not necessarily those of my employer)

In article <7hbfkr$lrv$1_at_nnrp1.deja.com>,   Tony Adolph <tony.adolf_at_viaginterkom.de> wrote:
> Hello All,
>
> I have three questions to ask:
>
> 1) I have a database built on RAID5 arrays. The drive letters for the
> arrays are not contiguous, i.e. there are two drive letters used for
> network connections, so the database lives on D: H: and I:. How can I
> ensure that these letters never get changed?
>
> 2) I am using a Compaq Proliant disk array. How can I view the disk
> read / write activity. I have tried Performance Monitor but always
get
> a flat line at zero no matter what scale I set. Is there another way,
> is there something like the unix sar for NT4?
>
> 3) Is it possible to build a stripe set across, say, 3 disks and then
> mirror these 3 disks to give data protection rather than use RAID5.
> The reason for the question is that I have read that RAID5 is quite
> slow for writes and our application is write intensive.
>
> I would appreciate any pointers, so thanks in advance
>
> Tony Adolph
>
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--== Sent via Deja.com http://www.deja.com/ ==-- ---Share what you know. Learn what you don't.--- Received on Wed May 12 1999 - 08:06:04 CDT